1. Field of the Invention
The present invention relates to a plasma display panel in which the structure of a partition wall formed on a rear substrate is improved.
2. Description of the Related Art
A plasma display panel (PDP) usually produces a discharge in a gas that is hermetically sealed between two substrates having electrodes, which generates ultraviolet rays. The ultraviolet rays excite phosphors, thereby displaying a desired image.
FIG. 1 shows a conventional PDP. Referring to FIG. 1, a front substrate 11 and a rear substrate 12 are located opposite to each other. Common electrodes 13 and scanning electrodes 14 alternate on the bottom surface of the front substrate 11 in a striped pattern. Bus electrodes 15 may be formed on the common and scanning electrodes 13 and 14 to reduce line resistance. A dielectric layer 16 on the bottom surface of the front substrate 11 embeds the common and scanning electrodes 13 and 14. A protective layer 17, for example, a MgO layer, may be formed on the dielectric layer 16.
Address electrodes 18 are formed on the rear substrate 12 crossing the common and scanning electrodes 13 and 14. The address electrodes 18 are embedded in a dielectric layer 19 with which the rear substrate 12 is coated. Partition walls 100 on the dielectric layer 19 are parallel to the address electrodes 18 in a striped pattern. Portions between the partition walls 100 are coated with phosphor layers 110 producing red, green and blue light.
The partition walls 100 may have various shapes. Each partition wall 100 is composed of a transparent white partition wall 100a having a predetermined height from the top of the dielectric layer 19 and a black partition wall 100b on the white partition wall 100a. The white partition wall 100a is provided to act as a reflector so as to improve the luminance efficiency of the phosphor layer 110 during discharge. The black partition wall 100b has a predetermined thickness so as to function as a black matrix.
In the conventional PDP having the above structure, once a voltage is applied between the scanning electrodes 14 and the address electrodes 18, pre-discharge occurs and wall charges are produced in the discharge space. In this state, when a voltage is applied between the common electrodes 13 and the scanning electrodes 14, a glow discharge occurs, thereby changing the gas into a plasma. Ultraviolet rays are emitted from the plasma and excite the phosphor layers 110, thereby displaying an image.
The phosphor layers 110 producing red, green and blue light are on the dielectric layer 19 and between the partition walls 100. In the conventional PDP 10, the light produced by the blue phosphor layers is relatively lower in luminance than the light produced by the red and green phosphor layers. To compensate for the low luminance from the blue phosphor layer, various methods have been developed. One method is to provide a blue phosphor layer that is wider than a red phosphor layer and a blue phosphor layer. Another method is to increase the luminance of a blue phosphor layer using an additional blue filter.
However, when enlarging the area of a blue phosphor layer to be wider than the area of a red phosphor layer and the area of a green phosphor layer, the size of a discharge cell defined by a pair of common and scanning electrodes 13 and 14, in which a sustain discharge occurs, is not uniform. Moreover, when an additional blue filter is used for improving the luminance of a blue phosphor layer, the structure of the PDP 10 becomes complicated.